/*
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * This software is open source.
 * See the bottom of this file for the licence.
 */

package com.googlecode.bluetools.dom4j.io;

import com.googlecode.bluetools.dom4j.Element;
import com.googlecode.bluetools.dom4j.ElementHandler;
import com.googlecode.bluetools.dom4j.ElementPath;

/**
 * <p>
 * <code>ElementStack</code> is used internally inside the {@link SAXContentHandler} to maintain a stack of
 * {@link Element}instances. It opens an integration possibility allowing derivations to prune the tree when a node is
 * complete.
 * </p>
 * 
 * @author <a href="mailto:james.strachan@metastuff.com">James Strachan </a>
 * @version $Revision: 1.1 $
 */
class ElementStack implements ElementPath {
	/** stack of <code>Element</code> objects */
	protected Element[] stack;

	/** index of the item at the top of the stack or -1 if the stack is empty */
	protected int lastElementIndex = -1;

	private DispatchHandler handler = null;

	public ElementStack() {
		this(50);
	}

	public ElementStack(int defaultCapacity) {
		stack = new Element[defaultCapacity];
	}

	public void setDispatchHandler(DispatchHandler dispatchHandler) {
		this.handler = dispatchHandler;
	}

	public DispatchHandler getDispatchHandler() {
		return this.handler;
	}

	/**
	 * Peeks at the top element on the stack without changing the contents of the stack.
	 */
	public void clear() {
		lastElementIndex = -1;
	}

	/**
	 * Peeks at the top element on the stack without changing the contents of the stack.
	 * 
	 * @return the current element on the stack
	 */
	public Element peekElement() {
		if (lastElementIndex < 0) {
			return null;
		}

		return stack[lastElementIndex];
	}

	/**
	 * Pops the element off the stack
	 * 
	 * @return the element that has just been popped off the stack
	 */
	public Element popElement() {
		if (lastElementIndex < 0) {
			return null;
		}

		return stack[lastElementIndex--];
	}

	/**
	 * Pushes a new element onto the stack
	 * 
	 * @param element DOCUMENT ME!
	 */
	public void pushElement(Element element) {
		int length = stack.length;

		if (++lastElementIndex >= length) {
			reallocate(length * 2);
		}

		stack[lastElementIndex] = element;
	}

	/**
	 * Reallocates the stack to the given size
	 * 
	 * @param size DOCUMENT ME!
	 */
	protected void reallocate(int size) {
		Element[] oldStack = stack;
		stack = new Element[size];
		System.arraycopy(oldStack, 0, stack, 0, oldStack.length);
	}

	// The ElementPath Interface
	//
	public int size() {
		return lastElementIndex + 1;
	}

	public Element getElement(int depth) {
		Element element;

		try {
			element = (Element) stack[depth];
		}
		catch (ArrayIndexOutOfBoundsException e) {
			element = null;
		}

		return element;
	}

	public String getPath() {
		if (handler == null) {
			setDispatchHandler(new DispatchHandler());
		}

		return handler.getPath();
	}

	public Element getCurrent() {
		return peekElement();
	}

	public void addHandler(String path, ElementHandler elementHandler) {
		this.handler.addHandler(getHandlerPath(path), elementHandler);
	}

	public void removeHandler(String path) {
		this.handler.removeHandler(getHandlerPath(path));
	}

	/**
	 * DOCUMENT ME!
	 * 
	 * @param path DOCUMENT ME!
	 * 
	 * @return true when an <code>ElementHandler</code> is registered for the specified path.
	 */
	public boolean containsHandler(String path) {
		return this.handler.containsHandler(path);
	}

	private String getHandlerPath(String path) {
		String handlerPath;

		if (this.handler == null) {
			setDispatchHandler(new DispatchHandler());
		}

		if (path.startsWith("/")) {
			handlerPath = path;
		}
		else if (getPath().equals("/")) {
			handlerPath = getPath() + path;
		}
		else {
			handlerPath = getPath() + "/" + path;
		}

		return handlerPath;
	}
}

/*
 * Redistribution and use of this software and associated documentation ("Software"), with or without modification, are
 * permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain copyright statements and notices. Redistributions must also contain a
 * copy of this document.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
 * following disclaimer in the documentation and/or other materials provided with the distribution.
 * 
 * 3. The name "DOM4J" must not be used to endorse or promote products derived from this Software without prior written
 * permission of MetaStuff, Ltd. For written permission, please contact dom4j-info@metastuff.com.
 * 
 * 4. Products derived from this Software may not be called "DOM4J" nor may "DOM4J" appear in their names without prior
 * written permission of MetaStuff, Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
 * 
 * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
 * 
 * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 */
